This paper is a study on the development of a haptic sensor system for monitoring skin conditions. The sensor is an assembly of layered media. The base of the sensor is a stainless plate, on which a sponge rubber, a PVDF film with electrode patches, a protective surface layer of acetate film and a gauge are stacked in sequence. The sensor is attached to the forefinger and pressed against the surface of the skin. It is then slid over the skin to collect surface morphological features. Through the fundamental experiment using the artificial objects, two evaluation parameters characterizing skin conditions are determined. One is the variance of the signal processed with a wavelet analysis, which is the index of roughness. The other is a parameter showing the dispersion of power spectrum density in the frequency domain, which is the index of softness. The sensor system is then applied to the clinical test of skin with various conditions. Results show that the sensor output well describes the skin conditions and represents the subjective evaluations of dermatologist.

View full abstract

Laser printers are most widely used non-impact printers that are primary output devices for PCs. The basis of the technology is digital electrophotography originally developed for copiers. In this paper, past, present, and future of the laser printer is reviewed with respect to basic electrophotography, digital technology, color technology, and environmental issue.

View full abstract

A new dual-stage actuator for positioning a magnetic head for high-density hard disk drives (HDDs) was proposed and developed. This dual-stage actuator device was characterized by applying the sputter-deposited thin film PZT, instead of the previously proposed bulk type PZT. The device performance was found outstanding with the peak-to-peak head displacement of 1.2 microns at the applied voltage of +/-5 volts, and the suspension resonance frequency higher than 15 kHz.

View full abstract

A spin stand which is used to evaluate read-write performance of magnetic heads and media can not become able to allow thermal drift of its mechanism and run out of its air spindle motor. Accuracy and mechanical stiffness of the spin stand supported the highly precise measurement of the magnetic recording. However, as an allowable tracking error will reach within 10nm, the future spin stand will need track follow with a fine actuator. A new PZT actuator which has characteristic of a resonance frequency 3.31 kHz and a displacement 7.24μm/50V has been manufactured. The analysis of the structure using FEM (finite element method) and control performance of the PZT actuator via the displacement feedback control system with DSP (Digital Signal Processor) has been discussed.

View full abstract

A suspension with IC-chip, what is called "Chip On Suspension (COS)" is most effective technology to increase data transfer rate of hard disk drives (HDDs). One of the most concern of COS is thermal affective of head suspension. This report is primary experimental study to control the temperature of COS. The temperatures of IC-chip were measured in a 3.5-inch type HDD. The experimental results are follows. Thermal conductance of IC-chip is almost proportional to its rotational Reynolds number. Thermal response time of IC-chip is almost in inverse to proportion to the square of its thermal conductance, These results are useful to determine the location of IC-chip, structure of FPC, and maximum continuous time of power supply to IC-chip. As a conclusion, it is possible to control the temperature of COS under the required temperature.

View full abstract

This paper describes a piezoelectric accelerometer that has unique and simple structure. This newly developed accelerometer is suitable for HDD (Hard Disk Drive) that is mounted in PC (Personal Computer). Piezoelectric ceramic is divided into two, therefore we can use the differential amplitude circuit. So, it realizes high S/N ratio, 10 dB higher than the conventional accelerometer in spite of the same size package. By using rotation of the polarized direction and the asymmetric division of the piezoelectric ceramic, we realize the nondirectivity accelerometer for shock detection and directivity accelerometer for rotational vibration detection. Our newly accelerometer has the smallest size package of 3.2*2.0*0.8 (mm) for shock detection and high sensitivity of 8 (mV/G) for rotational vibration detection.

View full abstract

In this paper, we propose a new head positioning mechanism of a magnetic disk storage. The new positioning mechanism is designed for 2.5 inch single disk and single side drive on the basis of the concept of the in-phase positioning mechanism. natural frequency of it's primaly resonance mode is about 12.4kHz. This positioning mechanism is actuated by a voice coil motor attached on the middle of the arm, which is more reliable device than other positioners with micro-actuator. In order to improve the shock durability, we propose a supporting mechanism of the disk drive. Analytical results indicate that a disk drive supported by the proposed mechanism has enough shock durability for 200kTPI.

View full abstract

This paper describes designing a controller of a hard disk drive for rejecting disturbances using mixed sensitivity approach. Position Error Signal (PES) is consist of Repeatable Runout (RRO) and Non-Repeatable Runout (NRRO), NRRO is decomposed into its contributing component which are force disturbance, mechanical vibration, and etc, in frequency domain. To simulate the behavior of the disturbance signals, the decomposed signals are transformed to time domain. The H^∞ control design can be eliminated such disturbances effectively. A mixed sensitivity approach is applied to the robust controller design of the track-following control for the HDD. We compare between the results with a conventional controller and the results with the proposed controller. it shows the validity of the proposed controller design method.

View full abstract

A simplified thermal analysis model has been developed for predicting the increase in internal temperature of an optical disc drive. This model represents heat dissipation paths in terms of the heat generated by the drive's parts and the sum of the paths' thermal resistances. The calculated results showed good agreement (within 20%) with experimental measurements of a DVD-RAM drive operating at double speed (2X). When this thermal analysis model was used to design a natural cooling system for a new optical disc drive, the resulting thermal resistance was 25% lower than that of a conventional drive.

View full abstract

A novel optical head slider for near-field recording is proposed. An air bearing pad pattern formed on the apex of cantilever-like polymeric waveguide, and using the cantilever itself as a suspension of slider, function of flying slider, suspension, and waveguide are all included into one body structure. This structure (flexible head slider) can be fabricated by the method similar to lithographical technique. This structure will be expected to have great advantages in miniaturization of head assembly, simplification of assembling and optical trimming process, and more, lightweight of head assembly brings wider tracking bandwidth. In this paper, we report the result of the readout signal evaluation of flexible optical head slider. Readout signal was obtained using a sample head slider with 0.22μm by 2.2μm aperture, scanning at linear velocity of 1.76m/s over the Cr-coated glass disk with sub-micron width Line-and-Space (L&S) pattern. The read-out of 0.2μm L&S pattern was successfully demonstrated at the contrast of 0.23. Stability of spacing control, signal to noise ratio, efficiency of optical system and the effect of minimizing aperture size was discussed.

View full abstract

Paper feeding systems with rubber-covered roller drive are widely used in information processingdevices such as copy machines, printers and ATM. It is important in their designs to control the paper velocity with precision. It's experientially known that the velocity ratio depends on many factors such as the normal force, the frictional coefficient and the rotative velocity. Therefore, in this paper, we deal with the effects of some factors on the velocity ratio by doing the experiment and the finite element analysis in the paper feeding system with rubber roller and bed.

View full abstract

Many kinds of paper sheets such as tickets, cards, bills, and checks, are widely used in the modern community. To handle such a variety of sheets, the sheet-stacking mechanism of a sheet-handling apparatus must be able to handle sheets of various sizes, rigidities, and coefficients of friction. Accordingly, we have developed a new sheet-stacking mechanism that can handle various sizes of sheets by means of looped plastic sheet attached to a roller. These looped sheets generate a breaking force that ensures the paper sheets are stopped correctly. To avoid jamming and incorrect stacking, the mechanism is designed so that the breaking force is in a practical range. Calculation and experiment showed that the new mechanism can stack sheets of various sizes successfully without jamming.

View full abstract

This paper describes a frictional characteristics of rubber rollers for a wide range of transport velocity (0.01〜10[m/s]) which covers almost every paper handling in office automation and in banking systems equipment. Frictional coefficients of rubber roller and paper sheet slightly decreases at high velocity and decreases at low velocity. We have also examined the differences of frictional characteristics among three types of experiments. We have found out that the frictional coefficient at low velocity differs with system of experiments, whether roller-fixed or roller-rotated. We have simulated these systems by non-linear finite element analysis. As a result, stick-slip seemed to have occurred at low velocity range. Roller-rotated is more affected by stick-slip and the frictional coefficient at low velocity is smaller than roller-fixed.

View full abstract

This paper describes theoretical and experimental study of steady-state characteristics of a paper feeder consisted of a short rubber-layered roller and a steel roller. It is assumed that the paper thickness and in-plane strain is infinitesimal and ignorable. Deformation and strain of surface of the rubber roller are culculated with our Green's function that has been derived under in-plane stress assumption with Boundary Element Method on cylindrical coordinates. In calurations, loading force between two rollers and paper tention are considered. Velocity ratios of paper feeding velocity to rubber roller velocity are derived from strain of the rubber roller. In order to confirm the numerical results, an experimental setup that consists of an endless paper and a paper feeding mechanism was prepared. Paper feeding velocity and rubber roller were measured experimentally. The experimental results agrees with the numerical ones.

View full abstract

Experimental and numerical investigations have been carried out on dynamics of electromagnetic particle chains in an electromagnetic field. Chains formed on a solenoid coil were observed and chain lengths and slant angles were measured. The chain length depends on both the density of magnetic particles and the magnetic flux density, but it is almost independent of the particle diameter. The inclination of a chain in the inclined magnetic field is enlarged by the gravitational force. The enlargement and collapse angle of a chain depend on magnetic flux density. These characteristics of chains and the chain forming process can be numerically simulated with the 3-D Distinct Element Method. Bead-carry-out phenomenon in a two-component development system in the laser printer was discussed by the comparison of calculated magnetic force and measured electrostatic force.

View full abstract

A basic research is being carried out in our laboratory on transport of particles in electrostatic traveling field to utilize it for laser printers. A particle conveyor was constructed. it consisted with parallel electrodes covered with insulating film on an acryl substrate. Traveling electrostatic waves were four-phases and rectangular shape with amplitude up to 1,000 volts, generated by function generators and amplifiers. The following were clarified by the experiment and numerical investigation : (1) Particles were transported almost linearly with time and the rate was also linear with applied voltage but a threshold existed due to adhesion force. (2) The direction of particle transport did not always coincide with that of the traveling wave but partially changed depending on the frequency of the traveling wave.

View full abstract

A preliminary experiment was conducted on an electrostatic ink jet phenomenon. High voltage was applied between an insulative capillary tube filled with water and a metal plate electrode. Ink jet phenomenon was observed at the dark discharge under conditions of appropriate tube diameter and water level. Although the electrostatic attractive force is small, in the order of 10 μN at the voltage lower than the corona onset, it is large enough to separate a water droplet against surface tension in the capillary tube at certain conditions. At the beginning of corona discharging, however, water mist was dispersed at wide angle from the tip of the tube. At higher voltage, water mist became to be dispersed like spray. Joule heat is assumed to be one of reasons of the mist generation. This phenomenon is expected to be utilized for a new ink jet print head.

View full abstract

To realize the quantitative evaluation of paper handling machines, we have developed original test media, the base material of which uses highly durable synthetic paper. With a special surface printing process and new technologies employed, the flexible and quantitative control of the specific characteristics of the media is ensured. Seven of them (the friction coefficient, deformation, thickness, scratch resistance, stiffness, anti-static performance, and adhesion of the medium to the rubber roller) greatly influence the paper handling performance of machines, The technology of friction coefficient control, in particular among them, is expected to be used for other applications as well. The inspection using these test media makes it possible to evaluate the paper handling performance of machines according to each medium characteristic quantitatively. Therefore, a reduction in the period of product development and the accumulation of reliable technologies as advantages are expected. Furthermore, a reduction in the processing period of products is expected from the production side as well along with the manufacture of high-quality products.

View full abstract